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triangulation of enemy fire

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In modern combat one of the hardest tasks is locating an enemy that is firing on you. With this system each squad or platoon member has helmet mounted or weapon mounted microphone that records the sound of enemy gunfire. An on- board processor then shares the information (via bluetooth, wifi, or whatever) with other team-members, and triangulates the sound source using each soldier's slightly different recording. In this way enemy combatants can be pinpointed. System can be calibrated to only hear AK-47 or your weapon of choice. Would work better the more distance there is between squadmembers, and the more datapoints there are.
simonj, Feb 15 2012

self-aiming rifle (at gunshot location) http://www.dailymai...-rolled-troops.html
[not_morrison_rm, Feb 15 2012]

//Consider a "solid" cylinder of transparent (and very viscous) gel, perhaps the size of a "barrel" of oil (about 55 gallons or 200 liters)// http://www.amazon.c...tiveASIN=B005MR3IVO
No need to imagine, just look & wonder! [DrBob, Feb 15 2012]

Gunfire Locator http://en.wikipedia...iki/Gunfire_locator
[Wrongfellow, Feb 15 2012]

SENTRI http://www.safetydynamics.net/
It also locates the source of explosions. Clever, that. [Alterother, Feb 16 2012]

[link]






       Using differential GPS and a "master" (probably the group leader) receiver, this could easily work. Whether it provides real-time useful information is another thing altogether. Capacity to interpret and act on a large volume of data realtime is the biggest challenge for a frontline leader in a combat situation. In that context, the human ear probably works well enough to direct supressing fire. Maybe someone with actual combat experience (mike?) can shed some real-world context?   

       I had thought I'd read something about a countersniper system used by the secret service for public events, that in essence did this but with fixed receiver locations. Realy only useful for catching the sniper, but still useful. Retribution still has value.
Custardguts, Feb 15 2012
  

       Did i say too much?I wonder about the usefulness of this in the complete opposite of what is suggested.   

       I have always imagined if i'm over-run by an invading force that after my family escapes i'll stick around and use firecrackers to draw fire in the wrong direction.
Zimmy, Feb 15 2012
  

       there was something in use in Northern Ireland during the Troubles, called Clarion or Ptarmigan or something like that. Can't find it on google. But, I did find the self-aiming rifle sight, see link.
not_morrison_rm, Feb 15 2012
  

       <link> that seems to be even better than what I thought up
simonj, Feb 15 2012
  

       This is well on the way to being Baked.   

       // Ptarmigan //   

       No, that's the frequency-agile secure battlefield radio. We could tell you more, but then we'd have to kill you.
8th of 7, Feb 15 2012
  

       Triangulation isn't really necessary. Consider a "solid" cylinder of transparent (and very viscous) gel, perhaps the size of a "barrel" of oil (about 55 gallons or 200 liters). We want the gel to be solid enough to not need a container. Any bullet that strikes this cylinder will leave a straight-line track in the transparent gel. So just shoot back along that line. More, the depth of penetration indicates how fast the bullet was travelling, and the angle of entry indicates the ballistic parabola it finished travelling. That data can be used to adjust the azimuth of the return fire.
Vernon, Feb 15 2012
  

       Useful for gunfights inside the Large Hadron Collider.
mouseposture, Feb 15 2012
  

       During WWII the Russian army sent prisoners towards the enemy; their task was simply to get shot, to help the Russians determine the Germans' position.
spidermother, Feb 15 2012
  

       //Triangulation isn't really necessary. Consider a "solid" cylinder of transparent (and very viscous) gel, perhaps the size of a "barrel" of oil (about 55 gallons or 200 liters).//   

       I am not wearing one of those strapped to my head just so someone can see which way the bullet came..
not_morrison_rm, Feb 15 2012
  

       Heh! Someone should film that. In fact, there should be a unit dedicated to filming all bizarre, halfbakery scenarios.
DrBob, Feb 15 2012
  

       //I am not wearing one of those strapped to my head//   

       If you were, I don't think you'd be of a size to worry about mere miniscule bullets.
RayfordSteele, Feb 15 2012
  

       Various cities I'm aware of (DC for certain, and I think Boston) have shot triangulation systems. Doing it with mobile recievers shouldn't be that difficult, although your accuracy would degrade by either the square or the cube of your locating system (I think cube, but don't feel like doing the math). My only concern is that those systems may need to be calibrated for the terain/acoustic effects, and that would be much more difficult (although not imposible, with a reference pulse) on the fly.   

       This would be of extremely limited use in a battlefield situation, because differentiating shots would be extremely difficult. For picking out a small ambushing force or individual sniper, it should work.
MechE, Feb 15 2012
  

       I very much like the halfbakedness of the barrel of jelly. Ballistic jelly appears on Mythbusters with some frequency. But you could accomplish something similar with a sensor integrated fabric made in two layers with a interposed jelly - a sandwich. The difference between where the two layers are hit by the incoming bullet would allow the computer to calculate where the shot came from.   

       It would be a bummer to have your bullet sensing sandwich all torn up by an IED, though. In modern batteles, I wonder what proportion of incoming missiles are single bullets fired by an individual, and how many are components of grenades, bombs etc.
bungston, Feb 15 2012
  

       Thinking further about the sensing sandwich or bowl full of jelly, I think that bullet velocity might be a wild card. Those short distances (jelly depth) probably would not depict how fast the bullet is going. A very aerodynamic bullet by a sniper 1 km away (he hates the cans!) might have a jelly trail very much like a tumbling nonaerodynamic round from an AK47 shot from down the block.
bungston, Feb 15 2012
  

       As [8th] mentioned, this technology is coming out of the oven as we speak, and it's not dependent on multiple separate components. There are quite a few Humvees rolling around Afghanistan with sonic-triangulation masts stuck to them. Can't for the life of me remember what the buggers are called.   

       [bungston], according to the DoD, an estimated 7-22% of projectiles in a pitched firefight are bullets.
Alterother, Feb 16 2012
  

       [DrBob] people who viewed your link also viewed Accoutrements Horse Head Mask, Fresh Whole Rabbit, and artificial testicles. it's a strange world..
simonj, Feb 16 2012
  

       I remembered: it's called SENTRI, and apparently it's now cooling on the sill <link>. Buy yours today!
Alterother, Feb 16 2012
  

       //[bungston], according to the DoD, an estimated 7-22% of projectiles in a pitched firefight are bullets.//   

       Which does tend to beg the question of the other 78-93%?   

       I'm guessing it breaks down to sticks and stones, empty beer cans, paper airplanes, dandruff driven to ballistic speed by the blast of nearby explosions and an unspecified amount of harsh language/cries of "take back what you said about my mother".
not_morrison_rm, Feb 16 2012
  

       This is interesting, but you're asking a lot of an audio program to differentiate between an AK and an AR. You could have transmitters on friendly guns that tell the system when they're firing so they can be left out of the triangulation I suppose.   

       Hey Vernon, put up your gel idea and I'll bun that, if for nothing else than a great idea for a movie scene. You could even use a drum of water for that matter.   

       So here's the scene, Bruce Willis and some hottie are pinned down by an unseen sniper. (Bruce didn't have time for backup so he went in alone.) The chick says "Where are the shots coming from?" and Bruce looks around and sees a 50 gallon drum full of rain water. So he runs behind it, stands up and takes a few wild shots in all directions to draw the sniper's fire then squats behind the drum. POW! The next sniper shot hits the drum and the water sprays out in the exact direction of the sniper revealing his location. Bruce looks at the stream, looks at where the stream is pointing and makes his move, working his way around to flank the sniper then "BAM!" after saying: (insert snappy remark here).   

       This would be one of the shootout scenes from "The Gun Juggler". Vernon, you'll get your name on the credits and be on the guest list at the premier's gifting suite.
doctorremulac3, Feb 16 2012
  

       I can just imagine the script getting through multiple redrafts and edits without anyone picking up that there's anything missing and, in the final edit of the movie, Bruce Willis saying "Hey babe, insert snappy remark here!".
hippo, Feb 16 2012
  

       I know a bit about the entertainment business, this sort of thing happens all the time.   

       I love the radio add where the guy says "After a week, you'll get your product and describe product in your own words here." then he starts laughing of course. They left it in because it was a comedy show but believe it or not, entertainers are humans who screw up all the time. Unlike the rest of the world though their lives get edited for release.
doctorremulac3, Feb 16 2012
  

       Rather than a jug of rainwater it should be a keg of beer. I can see the camerawork of the exploding plume of foaming beer, slowing down as it moves through space and the camera angle shifts to sight along the plume, then the focus shifts, blurring out the foam as you move forward along the path to show the sniper.   

       I like very much the idea that after shooting the sniper Bruce fills a glass from the pierced keg and walks over to the dying man to offer him a drink of beer. The man says thank you, takes a drink, takes another drink and then slumps; Bruce takes the glass from his hand before it spills and then finishes the beer.   

       My described sequence reminds me of the scene with the dying Union captain in The Good, the Bad and the Ugly. I encourage anyone who has not to watch that movie (especially you, 21Q); it is an amazing film and afterwards you will think about it often.
bungston, Feb 16 2012
  

       G.B.A. is one of the finest film/music combos ever made.   

       Like the beer idea, nice touch.
doctorremulac3, Feb 16 2012
  

       (Except it wouldn't work - if the bullet hits the keg off-centre it will make a hole, but the stream of beer will exit the keg perpendicular to the surface, not pointing towards where the bullet came from. However, Hollywood never bothers with physics accuracy)
hippo, Feb 16 2012
  

       For the Good, the Bad and the Ugly, there was a full orchestra on set playing the music, so that the actors could act in time to the music. Excellent - no one would bother doing that now.
hippo, Feb 16 2012
  

       //However, Hollywood never bothers with physics accuracy//   

       Bingo.   

       Although if it's a machine gun shooting the barrel and it peppers it all over, you average out the direction of the streams to find the point of launch assuming it hit the barrel evenly all over the side facing the shooter.   

       Your biggest issue is making it clear to the audience. If you had lots of holes, you could have him looking at them, perhaps holding up his hand in a karate chop position paralell to the furthest right hole, then the furthest left hole, then (with furrowed brow like he's calculating) slowley moving his hand to the center between the two and getting a "Got you sucker!" expression on his face.   

       Eh, I'd stick with the single stream, screw the details idea.   

       Ooohh, I've got the line right before he shoots the guy! "I knew that community college trigonometry degree would pay off some day!" BLAMM!   

       Alternate: He comes up behind the guy, who hears the Gun Juggler's gun cock, turns around and says "But how!" to which GJ says "4 years of community college trigonometry. Knew it would pay off some day." BLAMBLAMBLAMBLAM!!!
doctorremulac3, Feb 16 2012
  

       That Gun Juggler puts the "ee!" in repartee.
bungston, Feb 16 2012
  

       Got it.   

       You have a grenade deal that expands into a clear foam that acts like a ballistic gel and attaches itself to whatever object you throw it at. Picture a praying mantis egg cluster. You throw a couple of these things around and if the enemy hits it, you can see the bullet trace, including angle so you can get a rough estimate of distance.   

       So the enemy learns it's better not to hit these. Then you have a bunch of things the enemy doesn't want to shoot at around your position.
doctorremulac3, Feb 16 2012
  

       /You have a grenade deal that expands into a clear foam that acts like a ballistic gel and attaches itself to whatever object you throw it at/   

       Plus it is great for crowd control!
bungston, Feb 16 2012
  

       Yea, one if these things hits you in the face it's like: "Hey Hey! Ho Ho!..."(SPLAT!) "Mmm mmm mmmm mm mmm mm mm"
doctorremulac3, Feb 16 2012
  

       //        Which does tend to beg the question of the other 78-93%?    //   

       Shrapnel from grenades, mortars, artillery, missiles, plus ricochets and, yes, flying debris. The actual figures vary wildly based on what sort of resources the combatants can call upon. If nobody has a radio and everyone's run out of grenades, the percentage of lethal projectiles that are bullets will climb as high as 100%; however, given the wide array of support options available to a modern combat force such as the US Army or the Marines, it's theoretically possible for a platoon or even a squad (or just one guy with a pair of binoculars and a walkie-talkie) to conduct an entire combat encounter without actually firing a single shot from a pistol or rifle.
Alterother, Feb 17 2012
  

       paging [MikeD]...
RayfordSteele, Feb 17 2012
  
      
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